The present invention relates to an image display device which utilizes an emission of electrons into a vacuum space which is defined between two substrates; and, more particularly, the invention relates to an image display device which can produce a high-quality image display with low power consumption by leading out a current of high density from an electron source at a low voltage.
As a display device which exhibits high brightness and high definition, color cathode ray tubes have been widely used conventionally. However, along with the recent request for higher quality images in information processing equipment or television broadcasting, the demand for planar displays (panel displays) which are light in weight and require a small space, while exhibiting high brightness and high definition, has been increasing.
As typical examples, liquid crystal display devices, plasma display devices and the like have been put into practice. More particularly, as display devices which can realize higher brightness, it is expected that various kinds of panel-type display devices, including a display device which utilizes an emission of electrons from electron sources into a vacuum (hereinafter, referred to as “an electron emission type display device” or “a field emission type display device”, hereinafter also referred to as an “FED”), and an organic EL display, which is characterized by low power consumption, will be commercialized.
Among such panel type display devices, such as an FED particularly, a display device having an electron emission structure as proposed by C. A. Spindt et al, a display device having an electron emission structure of a metal-insulator-metal (MIM) type, a display device having an electron emission structure which utilizes an electron emission phenomenon based on a quantum theory tunneling effect (also referred to as a “surface conduction type electron source”), and a display device which utilizes an electron emission phenomenon having a diamond film, a graphite film or carbon nanotubes, are known.
An FED includes a back substrate on which cathode lines are formed, having electron-emission-type electron sources disposed thereon, and control electrodes disposed on an inner surface thereof, and a face substrate having anodes and fluorescent materials formed on an inner surface which faces the back substrate, wherein both substrates are laminated to each other by inserting a sealing frame between inner peripheries of both substrates, and the inside space thereof is evacuated. Further, to set a gap between the back substrate and the face substrate to a given value, gap holding spacers may be provided between the back substrate and the face substrate. As relevant examples of this type of device, reference is made to Japanese Unexamined Patent Publication Hei 10(1998)-134701 and Japanese Unexamined Patent Publication 2000-306508.